Accelerating multielectron reduction at Cu_xO nanograins interfaces with controlled local electric field

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Optimizing electrocatalysis for CO₂ reduction (CO₂RR) and nitrate reduction (NITRR) requires precise control over electron transport and local ion concentrations.
• Current synthetic methods and mechanistic understanding limit simultaneous optimization of kinetics and thermodynamics.

Purpose of the Study:

• To develop a novel synthesis approach for CuₓO bipyramids with controlled morphology for enhanced electrocatalytic performance.
• To elucidate the mechanistic relationship between electron transport, ion concentration, and electrocatalytic efficiency in CO₂RR and NITRR.
• To demonstrate the potential for simultaneous valorization of CO₂ and nitrate waste streams.

Main Methods:

• Laser-assisted manufacturing to synthesize CuₓO bipyramids with controlled tip angles and nanograins.
• Potassium/OH⁻ adsorption tests and finite element simulations to analyze electric field effects.
• In situ Fourier transform infrared spectrometry and differential electrochemical mass spectrometry for intermediate and product analysis.
• Theoretical calculations to understand thermodynamic contributions.

Main Results:

• Achieved 81% Faradaic efficiency for C₂₊ products at 900 mA cm⁻² for CO₂RR.
• Attained 81.83 mg h⁻¹ mg catalyst⁻¹ ammonia yield rate for NITRR.
• Demonstrated synergistic enhancement by coupling CO₂RR and NITRR systems.

Conclusions:

• Laser-assisted synthesis provides a method to precisely control catalyst structure for optimized electron transport and ion concentration.
• The developed CuₓO bipyramids show significant potential for efficient carbon and nitrogen cycling through simultaneous CO₂ and nitrate reduction.
• This approach offers a practical pathway for valorizing industrial flue gases and nitrate-containing wastes.